Best Practices In Sonography

Lower Extremity Venous Evaluation (Chronic Disease)

Mira L. Katz, Ph.D., R.V.T.
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina
Images provided by Cindy Owen, RDMS

Table of Contents

Type of Examination
Objective
Indication(s)
Limitations/Contraindications
Equipment & Supplies
Patient Preparation & Positioning
Technique
General Technical Points
Doppler
Deep Vein
Superficial Veins
Perforating Veins
Diagnostic Criteria
References

Diagnostic Criteria Table

Download the worksheet for Venous Duplex Imaging: Lower Extremity (chronic venous disease) (Word Document)

Type of Examination

Venous Duplex Imaging: Lower Extremity (chronic venous disease)

Objective

To identify the presence and duration of venous blood flow reversal (reflux) of the lower extremity

Indication(s)

  • Suspected chronic venous disease
    [pain, swelling, pigmentation changes, ulceration of the lower extremity]

Limitations/Contraindications

  • bandages, casts
  • abdominal and pelvic veins: depth of the vessels and the presence of bowel gas
  • calf veins: extensive swelling

Equipment & Supplies

  • Duplex imaging system: LOGIQ 700, LOGIQ 500
  • Transducers: 546L, 739L, LA39
  • System setups for venous ultrasound evaluation
  • Ultrasound gel
  • Towels
  • Materials for documentation of the study [video, prints, film]

Patient Preparation & Positioning

  • The venous ultrasound examination is explained to the patient and any questions are answered.
  • A history is obtained from the patient focusing on a previous history of deep and superficial venous thrombosis, and symptoms of chronic venous disease.
  • The examination is performed with the patient standing, holding onto a frame for support, and with full body weight placed on the contralateral leg.? The leg being examined should be slightly flexed at the knee.

Technique

General Technical Points

  • This examination should follow a complete evaluation of the lower extremity for venous thrombosis/obstruction.
  • Note the time of day the examination is performed.
  • Use a transverse view to locate the appropriate veins and then perform the venous Doppler examination from a longitudinal plane.?
  • Great care must be taken when evaluating a leg with an ulcer because it may be very painful for the patient.
  • At the end of the examination, the ultrasound gel should be removed from the patient and any excess gel should be removed from the transducer.? The transducer should be cleaned using a disinfectant.

Doppler

  • A transverse view is used to locate the veins at the appropriate level.
  • Once the vein is located, the examination for venous reflux is performed in the longitudinal plane since the absence or presence of venous reflux is measured using the venous spectral Doppler waveform (or color Doppler).
  • The Doppler sample volume is adjusted to the size of the vein's width.
  • No angle adjustment/correction is necessary since only blood flow direction and timing of venous reflux are measured.
  • The Valsalva maneuver is not used because of variable duration depending upon
    the patient.
  • Manual compression/release of the limb proximal and distal to the ultrasound transducer may vary depending on the examiner and the patient's limb size.? An automatic rapid cuff inflation/deflation device is suggested for standardized quantitative protocols.? The cuff should be placed on the limb distal to the ultrasound transducer for the most reliable results.
  • Cuff width and pressures:

    Thigh
    24 cm; 80 mmHg
    Calf
    12 cm; 100 mmHg
    Foot
    7 cm; 120 mmHg

  • Cuff inflation time is for approximately 3 seconds with a deflation time of 0.3 second.
  • Cuff distance from ultrasound transducer should be less than 5 cm.

Deep Veins ?

  • A linear array transducer should be used to evaluate for venous reflux in the deep veins of the lower extremity.
  • The transducer should be a low frequency linear array (739L 5MHz transducer).
  • The veins should be located in a transverse view and Doppler evaluation should be performed from a longitudinal plane.
  • The deep veins evaluated for venous reflux should include the common femoral, proximal superficial femoral, deep femoral (profunda), popliteal,
    and posterior tibial veins.

Superficial Veins

  • A linear array transducer should be used to evaluate for venous reflux in the deep veins of the lower extremity.
  • The transducer used may be a higher frequency linear array than the one used for evaluating the deep veins (LA39 9-13 MHz transducer).
  • The superficial veins evaluated for venous reflux should include the greater saphenous vein (near confluence with femoral vein, mid saphenous vein, and distally on the leg), and the lesser saphenous vein by its confluence with the popliteal vein.

Perforating Veins

  • The superficial and deep venous systems of the lower extremity are separated by the deep fascia (a echogenic horizontal line) and joined by perforating veins with valves that direct unidirectional blood flow from the superficial to the deep venous system.? There are approximately 90 to 150 perforators per lower extremity and most are found below the knee.? The direct perforators communicate between the superficial and deep veins and the indirect perforators interrupt their course in muscular veins before terminating
    in the deep veins.
  • A multi-frequency transducer is used to track the pathway of the perforating vein from the superficial to the deep venous system.
  • Although there are many perforators in lower extremity, most patients have 3 to 5 clinically significant incompetent perforators.? The distal medial calf is the location for clinically important perforating veins in many patients.? The calf should be evaluated in a standardized sequence starting just below the knee and scanning to the ankle.? This scanning technique is repeated, one width of the transducer's footprint at a time until completing the entire circumference of the limb searching for perforating veins.
  • Incompetence of the perforating vein is determined by using spectral Doppler waveform or color Doppler imaging.
  • Compression of the limb to augment venous blood flow is performed above and below the level of the perforator.? Direction of blood flow and the duration of reflux are documented.
  • The position of the incompetent perforating vein should be marked on the skin using a permanent skin marker (if requested by referring physician).? The mark on the skin should be the exact location where the vein perforates the deep fascia. The diameter of the perforating vein should be measured at this location.

Some common perforating veins are:

  • Cockett perforators: Mid to distal calf is the location for the Cockett perforators connecting the posterior arch vein (Leonardo's vein: off the greater saphenous vein) to the posterior tibial veins.? The Cockett I perforator is most distal and is located near the medial malleolus.? The Cockett II perforators are usually 7-9 cm above the lower border of the medial malleolus and the Cockett III perforators are located 10-12 cm above the medial malleolus.?
  • In the proximal calf there are the paratibial perforating veins that connect the greater saphenous vein to the posterior tibial veins or the popliteal vein.
  • Boyd's perforator: Just distal to the knee (proximal calf) is the Boyd's perforator, which connects the greater saphenous vein to the posterior tibial and muscular veins.
  • In the calf, perforators may be identified connecting branches of the greater and/or lesser saphenous veins directly to the anterior tibial veins.
  • The Bassi's perforator connects the lesser saphenous vein to the peroneal veins and indirect perforators off the lesser saphenous vein may connect with the gastrocnemius or soleal veins.
  • Dodd's perforators and Hunterian perforators are two named direct perforators located in the thigh.? The thigh segment of the greater saphenous vein is connected to the proximal popliteal or superficial femoral vein.?

Diagnostic Criteria

  • Direction of blood flow is documented by the Doppler spectral waveform or by color Doppler.
  • Reflux (retrograde venous blood flow) time is measured on the spectral Doppler waveform.? Reflux time less than 0.5 seconds is considered within normal limits and greater than 0.5 seconds is abnormal (some investigators use greater than 1 second).
  • The diameter of the perforating veins should also be measured and included in the report.
  • The report should specify which veins were examined and which were omitted because of technical difficulties.

Diagnostic Criteria

Venous Duplex Imaging: Lower Extremity
Chronic Venous Disease
(Click on images to enlarge.)

Interpretation

Gray scale

Doppler Signal /Color Doppler

Normal

Valve leaflets coapt

Perforators: less than 3mm in calf and 4mm in thigh

Reflux < 0.5 second

 

Abnormal

Lack of valve leaflet motion or failure of valve leaflets to coapt

Perforators: greater than
3mm in calf and 4mm in thigh

Reflux > 0.5 second

(Blood flow from deep to the superficial system)


References

Venous Duplex Imaging

Katz ML. Peripheral Venous Evaluation. In: Textbook of Diagnostic Ultrasonography. Hagen-Ansert SL (Ed). Chapter 22, pp. 531-547, Mosby, St. Louis, 2001.

Ridgway, DP. Introduction to Vascular Scanning. A guide for the complete beginner. Davies Publishing, 1998.

Sandri JL, Barros FS, Pontes S, Jacques C, Salles-Cunha SX. Diameter-reflux relationship in perforating veins of patients with varicose veins. J Vasc Surg 30:867-875, 1999.

van Bemmelen PS, Bedford G, Beach K, Strandness DE. Quantitative segmental evaluation of venous valvular reflux with duplex ultrasound scanning. J Vasc Surg 10: 425-431, 1989.

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